The majority in the Donbas are ethnic Ukrainians, not ethnic Russians. Sham referendums administered by a foreign military occupying force have not legitimacy and cannot be takes seriously as a true representation of the opinions of the people of the Donbas.
The Minsk II accords, of which you are so fond, required OSCE-supervised elections conducted under Ukrainian law, but the Russians refused to allow them. Instead, they staged their own illegal elections in violation of Minsk II just three months after signing the accord.
There are international pollsters whobdisagree with this notion.